Investigation on the anti-tumor efficacy by expression of GPI-anchored mIL-21 on the surface of B16F10 cells in C57BL/6 mice.

GPI-anchored membrane cytokines have been shown to play an important role in host immune response against tumor cells. In the present study, we constructed the tumor vaccine expressing mIL-21 in the GPI-anchored form and investigated its anti-tumor effect in C57BL/6 mice model. The fusion genes containing mIL-21 and the GPI anchor signal sequence was acquired by overlaping PCR, inserted into plasmid pcDNA3.1 to form the pcDNA3.1 mIL-21-GPI recombinant, which was transfected into the B16F10 cells, and the tumor vaccine based on B16F10 cells expressing the GPI-anchored membrane mIL-21 was generated. Through transfection, it was found that GPI-anchored membrane mIL-21 has no proliferate impact on B16F10 cells, but it was functional and reflected in inducing CD3-activated murine splenocytes proliferation response to B16F10 cells, improving the cytotoxicities of CTL and NK cells, increasing the numbers of splenocytes-producing IFN-gamma in mice, augmenting therapeutic effect of tumor and prolonging longevity effects in tumor-bearing mice injected with the inactivated GPI-anchored mIL-21 tumor vaccine. We concluded the expression of mIL-21 on the B16F10 cells surface in the GPI-anchored form was proved to be effective in activating immune responses against tumor cells, and our results provided a good foundation for further investigating the immunotherapy of tumor by GPI-mIL-21.